text: 
  #pragma once
  
  #ifndef COMMON_H_   /* Include guard */
  #define COMMON_H_
  
  #include <Arduino.h>
  #include <SoftwareSerial.h>
  #include <Adafruit_Thermal.h>
  
  const byte RX_PIN  = 14;
  const byte TX_PIN  = 12;
  const byte DTR_PIN = 16;
  const byte BUTTON  = 13;
  
  extern SoftwareSerial impSerial;
  extern Adafruit_Thermal impPrinter;
  
  void commonSetup();
  
  void serialPrint(char*);
  void serialPrint(char*, bool);
  void serialMode(byte);
  
  #endif // COMMON_H_
  